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GLASGOW AND WEST OF SCOTLAND SOCIETY OF ANAESTHETISTS
SOCIETY
NEWS
GLASGOW AND WEST OF SCOTLAND SOCIETY OF ANAESTHETISTS
Downloaded from http://bja.oxfordjournals.org/ at University of Iowa Libraries/Serials Acquisitions on June 20, 2015
THE third meeting of the 1955-56 session was The everyday precautions in anaesthesia to held in the Royal Faculty of Physicians and avoid carbon dioxide accumulation were menSurgeons, 242 St. Vincent Street, Glasgow, on tioned, stress being laid on adequate flow rates; January 19, 1956. The speakers were Dr. H. H. and ventilation. Investigations by Schwartz and Pinkerton and Dr. A. C. Macdonald, Western others had shown that flow rates of 8 Litres/ Infirmary, Glasgow. Their subject was "Aspects minute were required in the semi-open circuit to of Carbon Dioxide." prevent carbon dioxide accumulation. Dr Pinkerton was mainly concerned with the Methods of actual measurement of carbon carbon dioxide produced by the patient's metabol- dioxide levels were described, most being too ism. The use, and abuse, of carbon dioxide in the elaborate for everyday theatre use. The carbon past to hasten induction of anaesthesia and the dioxide analyser devised by the British Oxygen "de-etherization" of the patient was mentioned. Company was accurate to within 0.1-0.2 per cent, It was paradoxical that the respiratory depression and some observations made by Dr. Pinkerton sought nowadays by most anaesthetists was the with it were described. With patients breathing cause of acute interest in carbon dioxide and in the semi-open circuit, flow rates below 7-8 respiratory physiology. This interest had arisen litres/minute were insufficient to prevent carbon from the anaesthetist's daily use of assisted and dioxide accumulation. In apnoeic patients adequate controlled respiration. The treatment of some or overventilation kept carbon dioxide tensions medical conditions, through the extension of below normal, while easing off or stopping of modern anaesthetic techniques, was now within artificial respiration allowed carbon dioxide to the anaesthetist's province, e.g. ventilation of the accumulate. In favourable circumstances sponlungs in respiratory paralysis and the treatment of taneous respiration would recommence when (but r.espiratory acidosis in chronic bronchitis and not until) carbon dioxide levels rose to 5 per cent emphysema. plus. Controlled respiration, like normal respiration, There was clearly much scope for work on served a dual purpose—to supply oxygen and get carbon dioxide levels in our daily anaesthetic rid of carbon dioxide, the importance of the latter methods. often being overlooked. The results of stimulation Dr. Macdonald, speaking as a physician, of the respiratory centre by excess carbon dioxide believed that some of the problems of carbon were clear enough in the conscious person or in dioxide had relevance to patients requiring anaesone breathing spontaneously under anaesthesia. In thesia and that the help and co-operation of anaesthe apnoeic patient an increasing carbon dioxide thetists was of great value in some medical cases. tension stimulated the respiratory centre and The use of carbon dioxide, usually combined through it the vasomotor and cardiac centres, the with oxygen, was introduced in 1920 by Yandell clinical indications being sweating, vasodilatation, Henderson. In 1932 the first warning against oozing at the operation site, rising blood-pressure, carbon dioxide was made by Boothby, this warndisturbances of acid-base balance, cardiac arrhyth- ing being reiterated by Barach in 1940. The use of mias, continuing narcotic effects and postoperative carbon dioxide by physicians was now almost collapse. These effects could be produced by abandoned. hypoventilation. Hyperventilation with lowered Carbon dioxide, the first gas used to produce carbon dioxide tension was apparently less dis- anaesthesia by Hickman in 1820, was toxic. Work turbing and reasonably compatible with our wishes done on respiratory physiology as it affected subfor the anaesthetized case. marines had shown carbon dioxide poisoning to be143
144
BRITISH JOURNAL OF ANAESTHESIA
Printed in Great Britain by JOHN SHFRRATT & SON, Park Road, Altrincham
Downloaded from http://bja.oxfordjournals.org/ at University of Iowa Libraries/Serials Acquisitions on June 20, 2015
the cause of deterioration in men breathing oxygen respiratory infection or cardiac failure, is given under pressure. Lovelace, of B.L.B. fame, con- oxygen the anoxia is relieved, thus removing the cluded from experiments that a safe exposure to stimulus to respiration and so a fall in ventilation 5 per cent carbon dioxide was 5 minutes. The rate occurs. This leads to further carbon dioxide toxic effects of carbon dioxide were (1) cerebral retention and coma follows. The coma is caused (coma and epileptiform fits), (2) cardiovascular by reduced neurone oxygenation by an upset of (peripheral failure and cardiac arrhythmias), and the enzyme mechanism by either acidosis or the (3) the "off" effect—collapse, shock and rigors on carbon dioxide itself or both. The problem is reduction of the high CO2 blood level. whether the patient is better alert and anoxic or Normal control of respiration was by the effect comatose and oxygenated. The answer seemed to of carbon dioxide on the respiratory centre. There be to give oxygen only in amounts sufficient to was a carbon dioxide gradient from the tissues to raise blood saturation to safe levels and hope that the alveoli of the lung. Raising the alveolar carbon time and renal excretion of acids would allow the dioxide tension to 7 per cent progessively reduced patient's respiratory control to adjust itself. An the carbon dioxide excretion. Alveolar concentra- efficient patient-cycled respirator would allow tion above 7 per cent led to reversal of the gradient ventilation with adequate oxygenation. and carbon dioxide accumulation resulted. The application of carbon dioxide to medical cases should be limited to its use as a respiratory FACULTY NEWS stimulant for the collateral excretion of carbon monoxide and industrial contaminants such as The following are the names of the 23 candidates Trilene, in patients with normal respiratory and who were successful in their examination for the cardiovascular systems. Diploma of Fellow in the Faculty of AnaestheIn patients with respiratory abnormalities the tists, Royal College of Surgeons of England: use of carbon dioxide could be dangerous. In Ainley-Walker, J. C. S. Merrifield, A. J. respiratory obstruction carbon dioxide induced Anderson, J. L. Parker, Sheila Margaret hyperventilation, could raise the already large Brandstater, B. J. Phillips, A. H. Poon, Yee Kit intrapulmonary pressure and lead to fluid entering Burkinshaw, Daphne D'Bras. B. E. G. Prince-White. Freda the alveoli with the onset of pulmonary oedema. Delaney, E. J. Elizabeth This applied also in cardiac disease and pulmon- French, O. H. Rolfe, M. G. Schooling, Isabel Brenda ary infection. Collapse of the lung could be Genever, R. J. Jolley, C. R. Sims, A. J. worsened as the obstructive plug is only drawn Kaufman, L. Thomson, T. Keen, R. L. Webster, A. C. deeper into the affected segment. Laurie Smith, N. Wise. R. P. In emphysema chronic carbon dioxide retention Lumb. Patricia Mary Wright, D. G. R. exists. If the emphysematous patient, with acute Marshall, M. Young, T. M.
NEWS
GLASGOW AND WEST OF SCOTLAND SOCIETY OF ANAESTHETISTS
Downloaded from http://bja.oxfordjournals.org/ at University of Iowa Libraries/Serials Acquisitions on June 20, 2015
THE third meeting of the 1955-56 session was The everyday precautions in anaesthesia to held in the Royal Faculty of Physicians and avoid carbon dioxide accumulation were menSurgeons, 242 St. Vincent Street, Glasgow, on tioned, stress being laid on adequate flow rates; January 19, 1956. The speakers were Dr. H. H. and ventilation. Investigations by Schwartz and Pinkerton and Dr. A. C. Macdonald, Western others had shown that flow rates of 8 Litres/ Infirmary, Glasgow. Their subject was "Aspects minute were required in the semi-open circuit to of Carbon Dioxide." prevent carbon dioxide accumulation. Dr Pinkerton was mainly concerned with the Methods of actual measurement of carbon carbon dioxide produced by the patient's metabol- dioxide levels were described, most being too ism. The use, and abuse, of carbon dioxide in the elaborate for everyday theatre use. The carbon past to hasten induction of anaesthesia and the dioxide analyser devised by the British Oxygen "de-etherization" of the patient was mentioned. Company was accurate to within 0.1-0.2 per cent, It was paradoxical that the respiratory depression and some observations made by Dr. Pinkerton sought nowadays by most anaesthetists was the with it were described. With patients breathing cause of acute interest in carbon dioxide and in the semi-open circuit, flow rates below 7-8 respiratory physiology. This interest had arisen litres/minute were insufficient to prevent carbon from the anaesthetist's daily use of assisted and dioxide accumulation. In apnoeic patients adequate controlled respiration. The treatment of some or overventilation kept carbon dioxide tensions medical conditions, through the extension of below normal, while easing off or stopping of modern anaesthetic techniques, was now within artificial respiration allowed carbon dioxide to the anaesthetist's province, e.g. ventilation of the accumulate. In favourable circumstances sponlungs in respiratory paralysis and the treatment of taneous respiration would recommence when (but r.espiratory acidosis in chronic bronchitis and not until) carbon dioxide levels rose to 5 per cent emphysema. plus. Controlled respiration, like normal respiration, There was clearly much scope for work on served a dual purpose—to supply oxygen and get carbon dioxide levels in our daily anaesthetic rid of carbon dioxide, the importance of the latter methods. often being overlooked. The results of stimulation Dr. Macdonald, speaking as a physician, of the respiratory centre by excess carbon dioxide believed that some of the problems of carbon were clear enough in the conscious person or in dioxide had relevance to patients requiring anaesone breathing spontaneously under anaesthesia. In thesia and that the help and co-operation of anaesthe apnoeic patient an increasing carbon dioxide thetists was of great value in some medical cases. tension stimulated the respiratory centre and The use of carbon dioxide, usually combined through it the vasomotor and cardiac centres, the with oxygen, was introduced in 1920 by Yandell clinical indications being sweating, vasodilatation, Henderson. In 1932 the first warning against oozing at the operation site, rising blood-pressure, carbon dioxide was made by Boothby, this warndisturbances of acid-base balance, cardiac arrhyth- ing being reiterated by Barach in 1940. The use of mias, continuing narcotic effects and postoperative carbon dioxide by physicians was now almost collapse. These effects could be produced by abandoned. hypoventilation. Hyperventilation with lowered Carbon dioxide, the first gas used to produce carbon dioxide tension was apparently less dis- anaesthesia by Hickman in 1820, was toxic. Work turbing and reasonably compatible with our wishes done on respiratory physiology as it affected subfor the anaesthetized case. marines had shown carbon dioxide poisoning to be143
144
BRITISH JOURNAL OF ANAESTHESIA
Printed in Great Britain by JOHN SHFRRATT & SON, Park Road, Altrincham
Downloaded from http://bja.oxfordjournals.org/ at University of Iowa Libraries/Serials Acquisitions on June 20, 2015
the cause of deterioration in men breathing oxygen respiratory infection or cardiac failure, is given under pressure. Lovelace, of B.L.B. fame, con- oxygen the anoxia is relieved, thus removing the cluded from experiments that a safe exposure to stimulus to respiration and so a fall in ventilation 5 per cent carbon dioxide was 5 minutes. The rate occurs. This leads to further carbon dioxide toxic effects of carbon dioxide were (1) cerebral retention and coma follows. The coma is caused (coma and epileptiform fits), (2) cardiovascular by reduced neurone oxygenation by an upset of (peripheral failure and cardiac arrhythmias), and the enzyme mechanism by either acidosis or the (3) the "off" effect—collapse, shock and rigors on carbon dioxide itself or both. The problem is reduction of the high CO2 blood level. whether the patient is better alert and anoxic or Normal control of respiration was by the effect comatose and oxygenated. The answer seemed to of carbon dioxide on the respiratory centre. There be to give oxygen only in amounts sufficient to was a carbon dioxide gradient from the tissues to raise blood saturation to safe levels and hope that the alveoli of the lung. Raising the alveolar carbon time and renal excretion of acids would allow the dioxide tension to 7 per cent progessively reduced patient's respiratory control to adjust itself. An the carbon dioxide excretion. Alveolar concentra- efficient patient-cycled respirator would allow tion above 7 per cent led to reversal of the gradient ventilation with adequate oxygenation. and carbon dioxide accumulation resulted. The application of carbon dioxide to medical cases should be limited to its use as a respiratory FACULTY NEWS stimulant for the collateral excretion of carbon monoxide and industrial contaminants such as The following are the names of the 23 candidates Trilene, in patients with normal respiratory and who were successful in their examination for the cardiovascular systems. Diploma of Fellow in the Faculty of AnaestheIn patients with respiratory abnormalities the tists, Royal College of Surgeons of England: use of carbon dioxide could be dangerous. In Ainley-Walker, J. C. S. Merrifield, A. J. respiratory obstruction carbon dioxide induced Anderson, J. L. Parker, Sheila Margaret hyperventilation, could raise the already large Brandstater, B. J. Phillips, A. H. Poon, Yee Kit intrapulmonary pressure and lead to fluid entering Burkinshaw, Daphne D'Bras. B. E. G. Prince-White. Freda the alveoli with the onset of pulmonary oedema. Delaney, E. J. Elizabeth This applied also in cardiac disease and pulmon- French, O. H. Rolfe, M. G. Schooling, Isabel Brenda ary infection. Collapse of the lung could be Genever, R. J. Jolley, C. R. Sims, A. J. worsened as the obstructive plug is only drawn Kaufman, L. Thomson, T. Keen, R. L. Webster, A. C. deeper into the affected segment. Laurie Smith, N. Wise. R. P. In emphysema chronic carbon dioxide retention Lumb. Patricia Mary Wright, D. G. R. exists. If the emphysematous patient, with acute Marshall, M. Young, T. M.